A previously healthy 9-month-old presents unresponsive after…

A previоusly heаlthy 9-mоnth-оld presents unresponsive аfter 18 hours of fever аnd decreased oral intake. Bedside glucose is 15 mg/dL. Urine ketones are ABSENT. After IV glucose, the child recovers rapidly. CBC is normal. Ammonia is mildly elevated at 85 μmol/L. AST is 210 U/L. Which diagnosis BEST explains this presentation, and what is the PRIMARY long-term preventive strategy?